closed end pull rivet not so closed

started the day chasing down an obvious leak in the left tank... after searching unsuccessfully for some sign on the outside we pulled the tank from the wing and found that several of the ?closed? end pull rivets for the z brackets at stations 5 and 6 were not so closed after all. these special rivets have a partial depth mandrel that does not penetrate the rivet but air was bleeding through the pulled mandrel hole!

it is a bit of a concern that these closed end rivets are not a sure thing.

most of the builder sites that i have seen do not show proseal coverage over these rivet heads... as a preventive measure it would be advisable to go ahead and enclose the heads with proseal.

we cleaned everything up and sealed all of the closed rivets with proseal and pulled the right tank and did the same.

Steven,

You, me and others have had difficulty with AD-42-H rivets used to attach the "Z" brackets. Your difficulty is the latest report. I consider that blind rivet to be a marginal fastener in this application. I replaced most with Cherry rivets. This thread describes my "unpleasant" experience:

http://www.vansairforce.com/community/showthread.php?t=14228&highlight=unpleasant

I am just about to pressure test my left tank, so I don't know for sure yet but, I went ahead and covered those pop rivet heads anyway with Proseal. Just to look at those pop rivet heads didn't give me a lot of confidence in their sealability.

In fact, I globbed a lot of Proseal all over everwhere I thought fuel could escape on the inside of the tank. We'll see...